Assuming the belly has been in contact with the cure and/or brine the whole time, I'd go ahead and pull it. The initial moisture content and ratio of lean to fat can affect the feel of the curing/cured meat. If you leave the meat in the cure any longer, you'll likely have an overly salty chunk of bacon that will require blanching to make it palatable.

Of course, this should all be taken with a grain of salt, seeing as how I haven't been there to see what has been happening with the meat.

If it were mine, I would do as pthaloearth has suggested--cut off a bit of the meat, rinse it, and cook it up to see how it tastes. If it doesn't seem too salty, then I'd rub the cut edge with a little bit of the salt/sugar/pink salt mixture and give it another day or so.